Determining the proportion of heterozygotes using a normal mixture method of clustering: method applied to Pompe's disease in Brahman cattle.

A mutant allele which lowers the activity of alpha-glucosidase (GLU%) acts as a recessive lethal in cattle. The distribution of 29,370 GLU% values from Brahman cattle was subject to analysis by the normal mixture method of clustering to determine presumptive distributions of heterozygotes and normal homozygotes. The heterozygote distribution was found to overlap the distribution of homozygous normals over the whole of its range of GLU% values, the proportion of heterozygotes being estimated as 12%. The probability of heterozygosity was calculated over a range of GLU % values.